Opened 5 years ago

Last modified 11 months ago

#12957 new enhancement

Categories for finite (enumerated) sets

Reported by: nthiery Owned by: nthiery
Priority: major Milestone: sage-7.4
Component: categories Keywords:
Cc: sage-combinat, SimonKing, novoselt Merged in:
Authors: Reviewers:
Report Upstream: N/A Work issues:
Branch: Commit:
Dependencies: #12913 Stopgaps:

Description (last modified by mkoeppe)

There still remains a lot of finite (enumerated) sets that are not in the appropriate categories::

sage: CartesianProduct([1,2],[2,3]).category()
Category of enumerated sets
sage: Set([1,2,3]).category()
Category of sets
sage: (GF(3) ^ 2) in FiniteEnumeratedSets()
False
sage: MatrixSpace(GF(3),2) in FiniteEnumeratedSets()
False
sage: LatticePolytope(matrix(ZZ, [[1,1],[0,1]])).category()
Category of objects

See also: #12913

The following examples were originally in the ticket description but are good on sage-6.9.beta1

sage: Permutations().category()
Category of infinite enumerated sets
sage: DirichletGroup(5).category()
Category of finitely generated finite commutative groups

Moreover, with Sage 7.4.beta0 we now have:

sage: CartesianProduct([1,2],[2,3]).category()
... DeprecationWarning: CartesianProduct is deprecated. Use cartesian_product instead
See http://trac.sagemath.org/18411 for details.
  #!/usr/bin/env python
Category of Cartesian products of finite enumerated sets
sage: cartesian_product([[1,2],[2,3]]).category()
Category of Cartesian products of finite enumerated sets
sage: Set([1,2,3]).category()
Category of finite sets

Change History (6)

comment:1 Changed 4 years ago by jdemeyer

  • Milestone changed from sage-5.11 to sage-5.12

comment:2 Changed 3 years ago by vbraun_spam

  • Milestone changed from sage-6.1 to sage-6.2

comment:3 Changed 3 years ago by vbraun_spam

  • Milestone changed from sage-6.2 to sage-6.3

comment:4 Changed 3 years ago by vbraun_spam

  • Milestone changed from sage-6.3 to sage-6.4

comment:5 Changed 2 years ago by vdelecroix

  • Description modified (diff)

On sage-6.9.beta1 things get better... I modified the description accordingly

Last edited 2 years ago by vdelecroix (previous) (diff)

comment:6 Changed 11 months ago by mkoeppe

  • Cc novoselt added
  • Description modified (diff)
  • Milestone changed from sage-6.4 to sage-7.4

I have updated the description with the status as of version 7.4.beta0.

Regarding LatticePolytope (one of the examples in the description), I would be reluctant to consider it a finite enumerated set. There should be a distinction between the lattice polytope (an infinite set) and the set of its lattice points. The latter (which also makes sense for non-lattice polytopes) should be made a finite enumerated set.

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